What is CVE-2021-35327?

CVE-2021-35327 is a critical-severity vulnerability in Totolink A720r, classified under Missing Authorization. CVSS score: 9.8/10. Published 2021-08-05.

How severe is CVE-2021-35327?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2021-35327 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Auth bypass in Totolink A720r

CVE-2021-35327

A vulnerability in TOTOLINK A720R A720R_Firmware v4.1.5cu.470_B20200911 allows attackers to start the Telnet service, then login with the default credentials via a crafted POST request.

Vulnerability class: Broken Access Control

Published 2021-08-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.014 (71.1th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Totolink A720r
Totolink A720r Firmware — versions 4.1.5cu.470_b20200911

Weakness classification (CWE)

CWE-862 — Missing Authorization

Public proof-of-concept exploits

References

github.com/hurricane618/my_cves/blob/master/router/totolink/A720R_default_telne… (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-35327?: CVE-2021-35327 is a critical-severity vulnerability in Totolink A720r, classified under Missing Authorization. CVSS score: 9.8/10. Published 2021-08-05.
How severe is CVE-2021-35327?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-35327 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.